Electrolytic Purifier

ABSTRACT

An electrolytic device and method for generating a disinfecting solution that utilizes an electrical circuit and storage battery. The electrical circuit preferably conditions the power received from a variety of power sources to charge the storage battery and conditions the power stored in the storage battery to provide the appropriate power to maximize the disinfection efficacy of the disinfecting solution. The device may incorporate one or more other devices such as an LED, an electrical power takeoff, a clock, a compass, a transmitter device, a receiver device, a position locating device, a direction indicating device, and/or a camera.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of filing of U.S. Provisional Patent Application Ser. No. 61/019,914, entitled “Electrolytic Purifier”, filed on Jan. 4, 2008, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention (Technical Field)

The present invention relates to a small electrolytic disinfectant generator that preferably comprises a power conditioning circuit and a rechargeable battery that can be powered from other batteries, solar panels, or conventional utility electrical power.

2. Background

According to the World Health Organization, more than 25,000 people in the world die every day from water-borne diseases. Many grass roots level campaigns have been conducted by agencies such as the World Health Organization, the Pan American Health Organization, the Center for Disease Control and Prevention (CDC), US AID, many non-governmental organizations (NGOs), private non profit organizations, and private industries to try and solve this problem. Most of the current schemes involve some form of treatment technology that includes a consumable component. These solutions include distribution of bleach such as the Safe Water Program by the CDC, filtration systems by various organizations, distribution of sachets that contain flocculant aids and disinfectants (aka Pur® sachets), and various other schemes. One thing they all have in common is that they require a consumable component, and a logistics train to support continued use of the product. They typically require some continued recurring cost to the end user-end users who can not afford even the basic fundamentals in life. The present invention preferably does not require a significant consumable for continued use, just common salt, which is considered universally available. Once the device is distributed, continued use of the device would not require a new logistics train or consumables.

3. Description of Related Art

Note that the following discussion refers to a number of publications and references. Discussion of such publications herein is given for more complete background of the scientific principles and is not to be construed as an admission that such publications are prior art for patentability determination purposes.

Electrolytic technology utilizing dimensionally stable anodes (DSA) has been used for years for the production of chlorine and other mixed-oxidant solutions. Dimensionally stable anodes are described in U.S. Pat. No. 3,234,110 to Beer, entitled “Electrode and Method of Making Same,” whereby a noble metal coating is applied over a titanium substrate.

An example of an electrolytic cell with membranes is described in U.S. Pat. RE 32,077 to deNora, et al., entitled “Electrode Cell with Membrane and Method for Making Same,” whereby a circular dimensionally stable anode is utilized with a membrane wrapped around the anode, and a cathode concentrically located around the anode/membrane assembly.

An electrolytic cell with dimensionally stable anodes without membranes is described in U.S. Pat. No. 4,761,208 to Gram, et al., entitled “Electrolytic Method and Cell for Sterilizing Water.”

Various commercial electrolytic cells that have been used routinely for oxidant production may utilize a flow-through configuration that may or may not be under pressure that is adequate to create flow through the electrolytic device. Examples of cells of this configuration are described in U.S. Pat. No. 6,309,523 to Prasnikar, et al., entitled “Electrode and Electrolytic Cell Containing Same,” and U.S. Pat. No. 5,385,711 to Baker, et al., entitled “Electrolytic Cell for Generating Sterilization Solutions Having Increased Ozone Content,” and many other membrane-type cells.

In other configurations, the oxidant is produced in an open-type cell or drawn into the cell with a syringe or pump-type device, such as described in U.S. Pat. No. 6,524,475 to Herrington, et al., entitled “Portable Water Disinfection System.” This device utilizes batteries and an internal circuit to measure electrical current being delivered to the electrolytic cell. Various electronic components and software in the electrical circuit alarm for low salt and low battery condition, and ensure that adequate power is provided to the electrolytic cell to ensure that the oxidant generated by the device has maximum disinfection efficacy.

U.S. Pat. No. 6,736,966 to Herrington, et al., entitled “Portable Water Disinfection System”, the specification and claims of which is incorporated herein by reference, describes disinfection devices that utilize, in one instance, a cell chamber whereby hydrogen gas is generated during electrolysis of an electrolyte, and provides the driving force to expel oxidant from the cell chamber through restrictive check valve type devices. In this configuration, unconverted electrolyte is also expelled from the body of the cell as hydrogen gas is generated. In an alternate configuration in the same application, hydrogen gas pressure is contained in a cell chamber during electrolysis, but the pressure within the cell chamber is limited by the action of a spring loaded piston that continues to increase the volume of the cell chamber as gas volume increases. Ultimately, a valve mechanism opens, and the spring-loaded piston fills the complete volume of the cell chamber forcing the oxidant out of the cell chamber.

In the electrolytic cells utilizing titanium substrates with noble metal coatings as the anode, the pH at the surface of the anode is typically low, on the order of approximately 3. With sufficiently high brine concentration in the electrolyte, and sufficiently low voltage potential at the anode surface, oxygen generated at the anode surface reacts to form hypochlorous acid and other chlor-oxygen compounds with no oxygen gas liberated. Typical cathodes in these electrolytic cells may be composed of titanium, noble metal coated titanium, catalyst coated titanium, nickel based allows such as Hastalloy, stainless steel, and other conductive materials impervious to high pH conditions. As the cathode, hydrogen is liberated at the cathode surface with a localized high pH value at the cathode surface. During electrolysis, the metal comprising the cathode is not oxidized or otherwise damaged during electrolysis despite the production of hydrogen at the cathode surface. Over time, titanium hydride can form at the surface of a bare titanium cathode which may cause stress concentrations in the cathode surface. To preclude this hydride formation, noble metal or catalyst coatings can be applied to the cathode surface to prevent titanium hydride from forming on the cathode surface when the cathode substrate comprises titanium.

U.S. Pat. No. 7,015,654 to Kuhlmann, et al, describes a power conditioning circuit. A micro-controller and boost converter circuit provides constant current to a light emitting diode array or other energy consuming source such as an electrolytic cell. A micro-controller operatively coupled with a semiconductor switch and the boost converter circuit measure the ability of a DC power supply to change the inductor. Duty cycles of the semiconductor switch are modified according to the measurement so as to supply substantially constant current to the LED array or electrolytic cell through an inductor regardless of actual battery voltage.

SUMMARY OF THE INVENTION

The present invention is a portable electrolytic disinfectant generator comprising an electrolytic cell, a rechargeable battery, a power conditioning circuit for delivering a first predetermined electrical voltage and current to the electrolytic cell; and a charging circuit for conditioning power from a power source in order to generate a second predetermined electrical voltage to recharge the rechargeable battery. The power conditioning circuit preferably detects a salinity level of electrolytic solution in the electrolytic cell. The power source preferably comprises one or more solar cells. The generator is optionally hermetically sealed and/or buoyant. The generator preferably further comprises one or more elements selected from the group consisting of a light bulb, an LED, electrical contacts for receiving or discharging power, an external solar panel, an integrated solar panel, an electronic display, an attachment mechanism, a compass, a position finding device, a location beacon transmitter, a cell phone, a camera, a clock, a timer, and a mirror. The disinfectant is preferably selected from the group consisting of sodium hypochlorite, chlorine dioxide, bromine, and mixed oxidants.

The present invention is also a method for generating disinfectant, the method comprising the steps of conditioning power from a rechargeable battery to a first predetermined voltage and current, delivering the conditioned power to an electrolytic cell, electrolyzing brine, generating a disinfectant, conditioning power from a power source to a second voltage, and recharging the battery at the second voltage. The method preferably further comprising a function selected from the group consisting of detecting a salinity level of electrolytic solution in the electrolytic cell, terminating the recharging step when the rechargeable battery is fully charged, providing undervoltage shutoff if a power level of the rechargeable battery is below a predetermined threshold, providing overvoltage protection preventing the rechargeable battery from being damaged by overcharging, and sensing the input voltage from the power source in order to optimize charging of the rechargeable battery for different input voltages. The power source preferably comprises one or more solar cells. The method preferably further comprises the step of disposing the electrolytic cell in a portable case, preferably wherein the case is hermetically sealed and/or buoyant. The case is preferably sufficiently small to attach to a key fob or key ring, fit in a pocket, or hang from a neck chain or pocket chain. The case preferably further comprises one or more elements selected from the group consisting of a light bulb, an LED, electrical contacts for receiving or discharging power, an external solar panel, an integrated solar panel, an electronic display, an attachment mechanism, a compass, a position finding device, a location beacon transmitter, a cell phone, a camera, a clock, a timer, and a mirror. The disinfectant is preferably selected from the group consisting of sodium hypochlorite, chlorine dioxide, bromine, and mixed oxidants.

Objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated into and form a part of the specification, illustrate several embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating a preferred embodiment of the invention and are not to be construed as limiting the invention. In the drawings:

FIG. 1 is a system schematic of a rechargeable battery powered electrolytic disinfection device.

FIG. 2 is a view of a rechargeable battery powered electrolytic disinfection device with light emitting diodes.

FIG. 3 is a view of a rechargeable battery powered electrolytic disinfection device with light emitting diodes and an electrical power takeoff and recharging contacts.

FIG. 4 is a view of a rechargeable battery powered electrolytic disinfection device with light emitting diodes, electrical power takeoff and recharging contacts, and a detachable solar panel for recharging the device.

FIG. 5 is a view of a rechargeable battery powered electrolytic disinfection device with light emitting diodes, electrical power takeoff and recharging contacts, and an integral solar panel.

FIG. 6 is a view of a rechargeable battery powered electrolytic disinfection device with light emitting diodes, electrical power takeoff and recharging contacts, display for information, and an integral solar panel.

FIG. 7 is a view of a rechargeable battery powered electrolytic disinfection device in a small key fob configuration.

FIG. 8 is a view of a cylindrical electrolytic disinfection device made for batch oxidant generation.

FIG. 9 is a schematic of an embodiment of a circuit utilized in the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Production of disinfectant solutions via electrolysis is well documented in the literature. In the simplest embodiment, the process utilizes an anode electrode and a cathode electrode with a brine solution between the electrodes. Electrical energy is applied to the anode and cathode and transmitted to the brine solution, converting the brine solution to a disinfectant. In a typical electrolysis process, sodium chloride (salt) is added to water in an electrolytic cell chamber. The amount of disinfectant produced is typically a direct function of the amount of energy applied to the brine solution, and is typically independent of the concentration and volume of the brine solution. This feature is fortuitous from an operational standpoint because the operator does not need to closely control how much water is added to the electrolytic cell chamber, nor how much salt is added.

The present invention comprises an electrolytic device preferably powered by a rechargeable battery which is used to produce disinfectant solution. The device may comprise a stand-alone device or alternatively be mounted to a water storage container to disinfect the water in the storage container. The device can preferably be recharged from any number of energy producing devices.

An embodiment of an electrolytic disinfection device of the present invention preferably utilizes sodium chloride as a salt that is converted to brine and is electrolyzed to form sodium hypochlorite or chlorine based mixed oxidants as the disinfectant. Alternately, the device may use some other form of halogen to produce a disinfectant such as sodium hypochlorite, chlorine dioxide, bromine, or other such disinfectant that can be used for disinfection. The circuit to power the electrolytic cell preferably comprises a rechargeable battery and an electric circuit preferably to generate a pulsed direct current voltage of sufficient potential to generate a chlorine-based mixed oxidant solution. The electrical circuit also preferably integrates over voltage, under voltage, over current, and/or under current protection circuits to ensure the device is not damaged during charging or discharging of electrical power. The circuit also ensures that electrical conditions at the electrolytic cell are adequate to produce oxidant that is effective for the purpose of disinfection.

The rechargeable battery is preferably recharged using a solar panel. The device may also optionally incorporate other devices such as light emitting diodes (LEDs) or light bulbs for light generation or signaling, electrical terminals for providing an electrical potential to heat a resistance circuit to generate heat or flame, a global positioning system (GPS) location identification device, an electronic compass, a radio device, an emergency beacon transponder, a cell phone, a digital clock, a camera, a voice or music recorder, a data storage device, or other such electronic components.

After electrolysis of the salt water solution, the disinfectant produced in the process is added to a container of water to disinfect the water. Unconverted salt in the disinfectant solution is simply added to the water to be treated, thereby increasing the total dissolved solids (TDS) concentration in the treated water. Typically, the amount of unconverted salt added to the treated water is well below the taste threshold. What is typically important in the electrolysis process is control of the voltage and total current applied to the brine solution from the power source. The quality and strength of the oxidant are affected by the voltage and amperage applied to the electrolytic cell. Fortunately, these characteristics are easily controlled by an electrical circuit in the disinfectant device. The electrical circuit may comprise a microcircuit and/or a microcontroller that can be small and low cost. A schematic of one such circuit is shown in FIG. 9.

To ensure maximum flexibility of the device, the electrical circuit should be capable of delivering the desired voltage and amperage to the electrolytic cell. Some energy sources, such as a rechargeable battery, may not inherently produce the correct voltage for optimal production of the disinfectant, but the electrical circuit is preferably capable of conditioning the voltage to produce the correct voltage. Likewise, the rechargeable battery preferably used with the present invention can be recharged from a variety of different power sources including other batteries, solar panels, or other devices. Any of these charging devices may not produce the same voltage as the rechargeable battery in the device. Thus the electrical circuit may incorporate a switching regulator charging circuit controlled in such a way that the microcircuit and/or microcontroller senses the input voltage and drives the switcher to optimize the charging for different input voltages, such as those of a single alkaline battery (1.5V), single NiMH or NiCd battery (1.2V), lithium manganese battery (3V), small solar cell or panel (0.55V to 6V), lead acid battery (6V or 12V), or other such device.

The electrical circuit is preferably capable of conditioning the applied voltage such that the rechargeable battery is properly recharged. The electrical circuit will also preferably cease charging the rechargeable battery when it has become fully charged. A full recharge may optionally be indicated by a light emitting diode (LED) or other signaling device. The LED may also be utilized in the circuit to discharge excess power to avoid overcharging the rechargeable battery. One or more LED's may also be utilized to provide various indication functions for the device. For example, LED's may be utilized to indicate salinity that is too low or too high, battery voltage that is too low to run the cell, or completion of the charging cycle.

In the operational mode, the electrical circuit preferably ensures that the proper electrical conditions exist for the electrolysis process. During electrolysis, the voltage applied to the anode and cathode electrodes is preferably maintained constant throughout the entire process or the proper strength oxidant may not be produced. Low strength oxidant can result in less than optimum disinfection performance. The electrical circuit preferably maintains the appropriate voltage and amperage, and may provide an alarm to the user if performance is not within a specified range. Similarly, if low amperage draw is detected due to low brine concentration in the electrolytic cell, the circuit preferably provides an indication of a low salt condition (e.g. if the user did not add enough salt to the electrolytic cell).

The current can vary during electrolysis, so the circuit preferably measures the current provided to the electrolytic cell so that the desired dose of oxidants is produced. In addition, the circuit preferably “reads” the voltage of the power supply that is recharging the internal battery, conditions that incoming voltage properly to charge the internal battery, and protects the internal battery from overvoltage. For example, the internal battery may be a 3.5 volt battery. The circuit preferably boosts this voltage to provide an optimal voltage on the electrolytic cell.

In the embodiment of the present invention shown in FIG. 1, disinfection device 20 comprises electrolytic cell 22, electrical circuit 24 comprising microcontroller 25, rechargeable battery 26, solar panel 28, and electrolysis activation switch 32. Electrolysis activation switch 32 may optionally comprise a membrane switch or other type of hermetically sealed switch to avoid introduction of fluids or other elements to the inside of disinfection device 20. Water 36 is introduced into electrolytic cell 22 preferably followed by the addition of salt 34. Disinfection device 20 is held preferably vertically for several moments to allow salt 34 to dissolve in water 36 forming brine. Activation switch 32 is pressed thereby causing electrical current to be discharged from rechargeable battery 26 through electrical circuit 24 to electrolytic cell 22, wherein electrolysis converts the brine to disinfectant. After the energy in rechargeable battery 26 is partially or fully depleted, energy is restored to rechargeable battery 26 from solar panel 28 via electrical circuit 24. To further provide utility for disinfection device 20, the complete assembly can be hermetically sealed so that disinfection device 20 can be immersed under water or exposed to other harsh environments without damaging the device. Sealed disinfection device 20 may optionally be buoyant to avoid loss of disinfection device 20 in a body of water. In this embodiment, microcontroller 25 preferably drives electrical circuit 24 to run electrolytic cell 22 at a voltage different than the voltage of the rechargeable battery 26, and also controls the amount of current that is run through electrolytic cell 22 during the electrolysis process. Microcontroller 25 also preferably measures battery 26, controls for charge termination when the battery is fully charged, provides undervoltage shutoff if battery 26 gets too low and needs recharging, and provides overvoltage protection preventing battery 26 from being damaged by overcharging. Electrical circuit 24 also preferably senses the input voltage during recharge cycles, and drives the switcher to optimize the charges for different input voltages, thereby enabling different charging input voltages to charge battery 26.

In the alternative embodiment of the present invention shown in FIG. 2, disinfection device 40 comprises electrolytic cell 42, electrical circuit 44, rechargeable battery 58, solar panel 48, light emitting diodes 46, light emitting diode activation switch 50, and electrolysis activation switch 52. Water 56 is introduced into electrolytic cell 42 preferably followed by the addition of salt 54. Disinfection device 40 is preferably held vertically for several moments to allow salt 54 to dissolve in water 56. Activation switch 52 is pressed thereby causing electrical current to be discharged from rechargeable battery 58 through electrical circuit 44 to electrolytic cell 42 where the electrolysis process converts brine to disinfectant. After the energy in rechargeable battery 58 is depleted, energy is restored to rechargeable battery 58 from solar panel 48 via electrical circuit 44. Disinfection device 40 may also act as a flashlight by activating light emitting diode electrical switch 50 thereby illuminating light emitting diodes 46.

In the alternative embodiment of the present invention shown in FIG. 3, disinfection device 60 comprises electrolytic cell 62, electrolytic cell activation switch 64, light emitting diodes 66, light emitting diode activation switch 68, power contacts 70, and power contacts activation switch 72. Power contacts 70 can have two or more functions. To recharge the internal rechargeable battery, electrical leads from another power source can be connected to power contacts 70 via electrical connectors or electrical leads that incorporate magnets on the end of the external power leads to facilitate connection the power contacts 70. In this configuration, power flows to a rechargeable battery internal to electrolytic device 60. In an alternative configuration, power contacts activation switch 72 can be operated thereby allowing electrical current to flow from the internal rechargeable battery to the leads. In one embodiment of this configuration, power contacts 70 can be placed in contact with a suitable conductive material such as fine steel wool. When power contacts activation switch 72 is activated, power from the internal rechargeable battery can flow to power contacts 70 thereby creating an electrical heating circuit within the fine steel wool, thereby igniting the steel wool and starting a flame. A particularly aggressive and persistent fire can be generated when the fine steel wool is first impregnated with petroleum jelly. This embodiment is thus particularly useful for military personnel or outdoor enthusiasts. This single device would be capable of providing light, starting a fire, and disinfecting available drinking water from a stream, lake, or river, all of which are useful for outdoor survival.

In the embodiment of the present invention shown in FIG. 4, disinfection device 80 comprises electrolytic cell 82, electrolysis activation switch 84, light emitting diodes 86, light emitting diode activation switch 88, power contacts 90, power contacts activation switch 92, solar panel 94, and solar panel electrical contacts 96. After the energy in the internal rechargeable battery is partially or fully depleted, the rechargeable battery is recharged from solar panel 94 via electrical contacts 96. Electrical contacts 96 may also serve as the mechanical connection device between solar panel 94 and disinfection device 80.

In the embodiment of the present invention shown in FIG. 5, disinfection device 100 comprises electrolytic cell 102, electrolysis activation switch 104, light emitting diodes 106, light emitting diode activation switch 108, power contacts 110, power contacts activation switch 112, and integral solar panel 114.

In the embodiment of the present invention shown in FIG. 6, disinfection device 120 comprises electrolytic cell 122, electrolysis activation switch 124, light emitting diodes 126, light emitting diode activation switch 128, power contacts 130, power contacts activation switch 132, integral solar panel 134, and electronic display 136. Electronic display 136 may be used to communication information such as compass direction, position location signals, a clock display, a timer display, a cell phone display, a radio beacon display, or other such information. The display may have a large format screen to display any form of information including pictures, text, or other data, and that the screen can be touch sensitive or activated to provide input to the device including letters and text. Any of the functions of the device may optionally be voice activated.

In the embodiment of the present invention shown in FIG. 7, disinfection device 140 is configured in a very small package, such as a key fob or other small device, that may easily fit in a pocket, attach to a key ring, or hang from a neck chain or pocket chain. Disinfection device 140 comprises electrolytic cell 142, electrolysis activation switch 144, light emitting diodes 146, and light emitting diode activation switch 148.

In the embodiment of the present invention shown in FIG. 8, disinfection device 154 is configured in a form factor such that it can be dipped through the opening of a separate oxidant storage container. A brine solution can be made up in the separate oxidant storage container and the device can be dipped into it. Oxidant can then be created by using electrode circuit 153 to apply power to the electrolytic cell 150 after the electrolysis activation switch 152 is actuated by the user.

The present invention may also incorporate other devices or electronic components, including but not limited to a compass, a position finding device, a location beacon transmitter, a cell phone, a camera, a clock, a timer, and/or a reflection mirror.

Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference. 

1. A portable electrolytic disinfectant generator comprising: an electrolytic cell; a rechargeable battery; a power conditioning circuit for delivering a first predetermined electrical voltage and current to the electrolytic cell; and a charging circuit for conditioning power from a power source in order to generate a second predetermined electrical voltage to recharge said rechargeable battery.
 2. The generator of claim 1 wherein said power conditioning circuit detects a salinity level of electrolytic solution in said electrolytic cell.
 3. The generator of claim 1 wherein said power source comprises one or more solar cells.
 4. The generator of claim 1 wherein said generator is hermetically sealed and/or buoyant.
 5. The generator of claim 1 further comprising one or more elements selected from the group consisting of a light bulb, an LED, electrical contacts for receiving or discharging power, an external solar panel, an integrated solar panel, an electronic display, an attachment mechanism, a compass, a position finding device, a location beacon transmitter, a cell phone, a camera, a clocks a timer, and a mirror.
 6. The generator of claim 1 wherein said disinfectant is selected from the group consisting of sodium hypochlorite, chlorine dioxide, bromine, and mixed oxidants.
 7. A method for generating disinfectant, the method comprising the steps of: conditioning power from a rechargeable battery to a first predetermined voltage and current; delivering the conditioned power to an electrolytic cell; electrolyzing brine; generating a disinfectant; conditioning power from a power source to a second voltage; and recharging the battery at the second voltage.
 8. The method of claim 7 further comprising a function selected from the group consisting of detecting a salinity level of electrolytic solution in the electrolytic cell, terminating the recharging step when the rechargeable battery is fully charged, providing undervoltage shutoff if a power level of the rechargeable battery is below a predetermined threshold, providing overvoltage protection preventing the rechargeable battery from being damaged by overcharging, and sensing the input voltage from the power source in order to optimize charging of the rechargeable battery for different input voltages.
 9. The method of claim 7 wherein the power source comprises one or more solar cells.
 10. The method of claim 7 further comprising the step of disposing the electrolytic cell in a portable case.
 11. The method of claim 10 wherein the case is hermetically sealed and/or buoyant.
 12. The method of claim 10 wherein the case is sufficiently small to attach to a key fob or key ring, fit in a pocket, or hang from a neck chain or pocket chain.
 13. The method of claim 10 wherein the case further comprises one or more elements selected from the group consisting of a light bulb, an LED, electrical contacts for receiving or discharging power, an external solar panel, an integrated solar panel, an electronic display, an attachment mechanism, a compass, a position finding device, a location beacon transmitter, a cell phone, a camera, a clock, a timer, and a mirror.
 14. The method of claim 7 wherein the disinfectant is selected from the group consisting of sodium hypochlorite, chlorine dioxide, bromine, and mixed oxidants. 